The history of cell phones finds its birth around 1980. A batch of approximately 2000 mobile phones was manufactured in Chicago. The intended customers were given a free phone to see if that type of business would work. They were not the first cell phones manufactured, but they were the first to be mass produced.
The users found it so convenient to be able to quickly and easily call someone from wherever you were at the time. The initial cell phones were wieldy and cumbersome. In addition, they were unsightly as well as expensive.
Today the cell phone industry generates an astronomical $120 billion in revenues. That constitutes an apparent mega monster in anybodys book. Should one or two cell phones go awry, it would be understandable in light of the size of the networks.
However, in most cases you can still rebook a return flight to Hawaii while at the same time make a weather check in Boston. As far as communication is concerned, todays phones are versatile and worth their weight in gold.
It appears as if there is not much behind one mobile call because they are so easy to make. However, just attempting to explain the wireless networks can get perplexing. In point of fact, the wireless networks are a string of radio towers.
Only a few miles separate each tower as they form what looks like a vast grid. The space from one tower to the next is called a cell. The landline telephone network is also connected to the towers. When you call someone on your handset, it searches for a signal from a cell tower.
If your handset cannot find a signal you will not be able to make a call. A major requirement for all cell phones is to have a System Identification Code, SID. It is a unique five digit number. The FCC assigns this number to each carrier.
The SID code is put into your handset after you sign a service contract. Then the phone is activation. When you turn your mobile phone on it searches for a SID on the control channel. Your cell phones inability to retrieve it results in the dreaded no service message being displayed on your phone.
Conversely, should a SID be found, the SID in the handset tries to match up with the SID that was located. When a match is made your cell realizes that it is working from home base.
Should they not match up, your mobile is said to be roaming. The system manager that your phone is roaming in, contacts the manager of your home system. Then your system manager checks its own database to confirm that your SID is valid. Your phone is then tracked as it roams through the various cells. Using someone elses network like that means added costs. The truth of the matter is roaming can hurt your pocket.
